The water in ponds and aquaria tends to become dirty over time due to an accumulation of algae and other debris. Accordingly, water filters are known which include a chamber including filter media. The filter media may comprise open cell foam, sand, or other elements some, or all, of which may be substantially inert relative to the water. The water is passed through the filter chamber, and hence the filter media, such that the debris is substantially removed from it. However, over time the accumulation of debris reduces the efficiency of the filter media such that either the exiting water remains dirty or such that the filter media becomes effectively blocked. This results in water overflowing, or by-passing, the filter media. Alternatively, or additionally, the flow-rate through the filter media may become reduced due to back-pressure created in the system. When this occurs the filter media needs to be cleaned.
There are several different ways in which filter media may be cleaned. One way is to remove the filter media and wash it. This is relatively easy for homogenous filter media such as blocks of open cell foam. Another way is to temporarily reverse the flow of water through the chamber using fresh water and redirect the exiting water away from the pond.
These methods do provide some cleaning of the filter media but where it is comprised of a plurality (possibly a multitude) of discrete elements it is time consuming and difficult for a user to remove them from the chamber and wash them. Moreover, the discrete elements tend to clump together into a “block” due to the accretion of debris. If reverse flow is used solely as a cleaning method channels within the block are created but the elements substantially stay adhered to one another. Such a “block” of elements has severely reduced filtering properties and accordingly, during cleaning it is important that the block is broken up into its constituent elements.
One way to do this is to use paddles which may be rotated within the block. However, the paddles are provided in the filter chamber before filtering operations commence and thus become embedded in the “block”. Rotation of the paddles usually results in only partial break-up of the “block”.
Discrete filter media elements also tend to adhere to the interior walls of the filter chamber. This may include the side wall(s) and/or the base, and/or if the media floats, the lid. If typical cleaning methods are used such as reverse flow or paddles, some of the elements remain adhered to the interior walls and act as “seeding points” for adhesion of further elements after the resumption of filtering operations.
Accordingly, there is a need for improved apparatus for the breaking up of discrete filter media elements to improve the cleaning of water filters.